Checkpoint blockade immunotherapy is an innovative treatment that uses medications known as immune checkpoint inhibitors to address several types of cancer. As is true of other types of immunotherapies, checkpoint inhibitor therapy attempts to tweak your body’s natural immune system to improve its ability to fight off infections and diseases. Specifically, the medications used in checkpoint blockade treatment can help the body’s immune system recognize and attack cancerous cells.
How do immune checkpoint inhibitors work?
To understand how checkpoint inhibitor drugs work, it’s helpful to consider how your body’s immune system works. Let’s start by looking at the roles of:
- T cells — white blood cells, or lymphocytes, that attack potentially harmful cells to protect your body from infection
- Antigens — unique protein molecules on the surface of various types of cells
- Immune checkpoint proteins — modulators that help prevent over-aggressive immune responses
Different types of antigens can be found on both normal, healthy cells and harmful cells like viruses and bacteria that can invade your body. They can also be present on some cancer cells. These antigens serve as identification tags or markers that T cells use to distinguish between harmless cells that belong in the body and potentially harmful cells that must be destroyed.
The T cells also carry protein molecules, including some known as immune checkpoint proteins. Essentially, these checkpoint proteins help regulate your body’s immune response. Their job is to stop a T-cell attack on harmful cells once the threat is eradicated. This is a critical function because an uncontrolled immune response can cause serious inflammatory tissue damage and trigger autoimmune diseases.
Unfortunately, some types of cancer exploit the immune system's checkpoint safeguards by tricking them into identifying cancer cells as healthy cells, thus preventing a T-cell attack or halting it before the cancer cells have been destroyed. This allows cancerous cells to avoid detection and continue to spread.
Immune checkpoint inhibitors are drugs that block checkpoint proteins, effectively "releasing the brakes" on the immune system to better fight the cancer. There are several drugs approved by the Food and Drug Administration (FDA) for use in checkpoint blockade immunotherapy, and research toward developing additional medications is ongoing.
What types of cancer are targeted by checkpoint inhibitor drugs?
Checkpoint blockade immunotherapy has shown promise in treating a variety of malignancies, including:
- Breast cancer
- Cervical cancer
- Colon cancer
- Liver cancer
- Stomach cancer
- Lung cancer
- Kidney cancer
- Bladder cancer
- Hodgkin’s lymphoma
- Ovarian cancer
Some examples of cancers that have been resistant to checkpoint inhibitors include prostate cancer, glioblastoma (brain tumor) and pancreatic cancer. Moreover, results of this type of immunotherapy can vary from one patient to another, even if both have the same type of cancer.
Still, the use of checkpoint inhibitors is considered a major advancement in cancer treatment, and researchers continue to fine-tune checkpoint blockade therapy to improve its efficacy. One of the approaches underway is to combine the use of checkpoint inhibitors with other immunotherapy treatments, such as cancer vaccines and cellular immunotherapy.
What is the role of checkpoint blockade immunotherapy at Moffitt?
At Moffitt Cancer Center, we recognize that every patient is unique and requires a personalized approach to combating cancer. Depending on a patient’s diagnosis and other individual factors, our treatment plans may include a combination of therapies, including checkpoint blockade inhibitors, cellular immunotherapy, radiation and chemotherapy.
Cellular immunotherapy is a very active area of research at Moffitt, and we continue to make great strides in increasing its effectiveness and expanding its use in cancer treatment. Our outstanding research program is widely acclaimed and has received national recognition in the form of a Comprehensive Cancer Center designation from the National Cancer Institute. Additionally, our cancer specialists incorporate cellular immunotherapy in treatment plans for their patients as appropriate. Some examples are:
CAR T-cell therapy
Chimeric antigen receptor (CAR) T-cell therapy involves harvesting a patient’s T cells, genetically modifying them to recognize the unique proteins present on the surface of certain cancer cells and then infusing them back into the patient’s body. This modification unleashes the patient’s natural ability to destroy the cancerous cells while leaving the healthy cells intact. CAR T-cell therapy is FDA-approved for patients with certain types of blood and bone marrow cancers, and there are additional eligibility requirements.
Also known as T-cell receptor gene therapy, this treatment has shown promise in clinical trials and recently received FDA approval as a therapeutic for certain types of cancerous tumors. It is similar to CAR T-cell therapy in that TCR therapy involves collecting T lymphocytes from a patient’s blood, genetically modifying them and then returning them to the patient. However, the method of modifying the lymphocytes differs between the two immunotherapies.
Tumor-filtrating lymphocyte (TIL) therapy bolsters the ability of T cells collected from a cancerous tumor to destroy the tumor itself. Generally, the approach involves harvesting the lymphocytes and growing them in a laboratory until they’ve multiplied into billions, then re-infusing them into the patient.
Part of our personalized approach to cancer treatment
Moffitt is a nationally ranked cancer center that delivers care in new and transformative ways. Our patients not only have access to checkpoint blockade immunotherapy and other advanced treatments but can also benefit from our robust clinical trials program. Taking a multispecialty approach to cancer treatment, we can match patients with various clinical trials that are appropriate for their unique needs.
If you’d like more information about checkpoint blockade immunotherapy, contact Moffitt Cancer Center at 1-888-663-3488 or complete a new patient registration form online. Your cancer diagnosis is our top priority, and we’re committed to connecting you with a cancer expert as soon as possible.
National Cancer Institute: Checkpoint Inhibitors
National Cancer Institute: Which Cancers Are Treated With Immune Checkpoint Inhibitors
eCancer.org: Why Are Some Cancers Unresponsive to Checkpoint Inhibitors